a A 2-year moving average is presented, based on data from the year indicated and the previous year. For data before 2005, the 1977 Office of Management and Budget (OMB) Standards for Data on Race and Ethnicity were used to classify persons into one of the following four racial groups: White, Black, American Indian or Alaskan Native, or Asian or Pacific Islander. The revised 1997 OMB Standards were used for data for 2006 and later years. Persons could select one or more of five racial groups: White, Black or African American, American Indian or Alaska Native, Asian, or Native Hawaiian or Other Pacific Islander. In 2005, half of the sample received the earlier version of the question and half received the later one, and their data were combined. Included in the total but not shown separately are American Indian or Alaska Native, Asian, Native Hawaiian or Other Pacific Islander, and "Two or more races." Beginning in 2006, those in each racial category represent those reporting only one race. Data from 2006 onward are not directly comparable with data from earlier years. Hispanics may be of any race.